CN112702037A - Lamb wave resonator with POI structure - Google Patents
Lamb wave resonator with POI structure Download PDFInfo
- Publication number
- CN112702037A CN112702037A CN202011508678.2A CN202011508678A CN112702037A CN 112702037 A CN112702037 A CN 112702037A CN 202011508678 A CN202011508678 A CN 202011508678A CN 112702037 A CN112702037 A CN 112702037A
- Authority
- CN
- China
- Prior art keywords
- piezoelectric layer
- thickness
- wave resonator
- lamb wave
- lambda
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 235000019687 Lamb Nutrition 0.000 title claims abstract description 52
- 239000000463 material Substances 0.000 claims abstract description 28
- 239000000758 substrate Substances 0.000 claims abstract description 22
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 7
- 229910052681 coesite Inorganic materials 0.000 claims description 6
- 229910052906 cristobalite Inorganic materials 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 229910052682 stishovite Inorganic materials 0.000 claims description 6
- 229910052905 tridymite Inorganic materials 0.000 claims description 6
- 229910003327 LiNbO3 Inorganic materials 0.000 abstract 1
- 230000005284 excitation Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 182
- 230000008878 coupling Effects 0.000 description 40
- 238000010168 coupling process Methods 0.000 description 40
- 238000005859 coupling reaction Methods 0.000 description 40
- 238000010586 diagram Methods 0.000 description 35
- 229910052751 metal Inorganic materials 0.000 description 8
- 239000002184 metal Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 238000000034 method Methods 0.000 description 3
- 238000010897 surface acoustic wave method Methods 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 238000000623 plasma-assisted chemical vapour deposition Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/02228—Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
Abstract
The invention provides a lamb wave resonator with a POI structure. The lamb wave resonator may include: a substrate of a high acoustic velocity material; and a piezoelectric layer located above the high acoustic velocity material substrate, the piezoelectric layer having a first interdigital transducer and a second interdigital transducer respectively arranged on an upper surface and a lower surface thereof, wherein interdigital electrodes of the first interdigital transducer and the second interdigital transducer are opposite to each other in a stacking direction across the piezoelectric layer and have the same electrode width, electrode thickness, electrode pitch, and excitation acoustic wave wavelength λ, the interdigital electrodes are all embedded in the piezoelectric layer, wherein the material of the piezoelectric layer is YX-LiNbO3 having a cut angle θ, wherein θ is 30 ° ≦ θ ≦ 60 °, and the thickness t of the piezoelectric layer is 0.3 λ -0.6 λ.
Description
Technical Field
The invention relates to the field of mobile phone radio frequency, in particular to a lamb wave resonator with a POI structure.
Background
The development of 5G handset filters requires lower loss, higher frequencies and greater bandwidth, which presents a significant challenge to existing Surface Acoustic Wave (SAW) and Bulk Acoustic Wave (BAW) technologies, which are generally limited by the effects of spurs. In order to meet the requirement, a Lamb wave structure is proposed recently, which mainly adopts a plate wave mode, has a high acoustic velocity, and shows application advantages in sub-6GHz and millimeter wave mobile communication. In the lamb wave resonator, the main mode is lamb wave, and the rayleigh wave mode is a spurious mode. The presence of spurious modes can affect the performance of the resonator, such as by degrading the Q value (quality factor). How to improve the electromechanical coupling coefficient and inhibit the spurious effect is one of the key problems faced by lamb wave resonators.
Disclosure of Invention
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
To solve the above problems, the present invention aims to provide an improved lamb wave resonator structure having a POI structure, which has advantages of high electromechanical coupling coefficient and small stray.
According to an aspect of the present invention, there is provided a lamb wave resonator having a POI structure, the lamb wave resonator comprising:
a substrate of a high acoustic velocity material; and
a piezoelectric layer located above the high acoustic velocity material substrate, the piezoelectric layer having an upper surface and a lower surface on which a first interdigital transducer and a second interdigital transducer are respectively disposed, wherein interdigital electrodes of the first interdigital transducer and the second interdigital transducer are opposite to each other in a stacking direction across the piezoelectric layer and have the same electrode width, electrode thickness, electrode spacing, and excited acoustic wave wavelength λ, and the interdigital electrodes are all embedded in the piezoelectric layer, wherein
The piezoelectric layer is made of YX-LiNbO with a cut angle theta3Wherein θ is 30 ° ≦ θ ≦ 60 °, and the thickness t of the piezoelectric layer is 0.3 λ -0.6 λ.
According to a further embodiment of the present invention, the chamfer angle θ and the thickness t of the piezoelectric layer each take on one of the following combinations:
θ is 30 °, 50 ° or 60 °, t is 0.6 λ;
θ 35 °, t 0.3 λ -0.4 λ or 0.6 λ;
theta is more than or equal to 40 degrees and less than or equal to 45 degrees, and t is 0.3 lambda-0.6 lambda; and
θ＝55°，t＝0.5λ－0.6λ。
according to a further embodiment of the present invention, the chamfer angle θ and the thickness t of the piezoelectric layer each take on one of the following combinations:
θ＝35°，t＝0.3λ－0.4λ；
θ＝50°，t＝0.6λ；
θ is 55 °, t is 0.6 λ; and
θ＝60°，t＝0.6λ。
according to a further embodiment of the invention, the high acoustic speed material is 4H-SiC, 3C-SiC or 6H-SiC.
According to a further embodiment of the present invention, the lamb wave resonator further comprises: a layer of low acoustic velocity material dielectric disposed between the high acoustic velocity material substrate and the piezoelectric layer.
According to a further embodiment of the invention, the material of low acoustic velocity is SiO2And the thickness is 0.075 lambda-0.1 lambda.
According to a further embodiment of the present invention, a dielectric layer material is plated on the other side surface of the piezoelectric layer opposite to the high sound velocity material substrate.
According to a further embodiment of the present invention, the dielectric layer material is SiO2Or SiN with a thickness of 0.05 lambda-0.1 lambda.
According to a further embodiment of the invention, the wavelength λ is 2 μm.
According to a further embodiment of the invention, the substrate of a high acoustic velocity material has a thickness of 5 λ, the electrode width is 0.25 λ, the electrode spacing is 0.25 λ and the electrode thickness is 200 nm. .
Compared with the scheme in the prior art, the lamb wave resonator provided by the invention at least has the following advantages:
1. by controlling the cutting angle of the piezoelectric layer and the thickness of the piezoelectric layer, the lamb wave resonator can have higher electromechanical coupling coefficient and high Q value, and the main mode has no stray or very small stray;
2. by interposing a layer of low acoustic velocity between the piezoelectric layer and the high acoustic velocity substrateDielectric layer of material (e.g. SiO)2) The Temperature Coefficient of Frequency (TCF) can be reduced; meanwhile, the dielectric layer of the low sound velocity material and the high sound velocity substrate form a reflecting layer to prevent sound waves from leaking from the direction of the substrate, so that the lamb wave resonator has a high Q value.
These and other features and advantages will become apparent upon reading the following detailed description and upon reference to the accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description are explanatory only and are not restrictive of aspects as claimed.
Drawings
So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only some typical aspects of this invention and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects.
Fig. 1 is a schematic diagram of a saw interdigital transducer.
Fig. 2 is a cross-sectional view showing the structure of lamb wave resonator 100 according to one embodiment of the invention.
Fig. 3 is a partially enlarged schematic view of a lamb wave resonator.
Fig. 4(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 30 deg. and a piezoelectric layer thickness h of 0.3 λ -0.6 λ.
Fig. 5(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 35 deg. and a piezoelectric layer thickness h of 0.3 lambda-0.6 lambda.
Fig. 6(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 40 ° and a piezoelectric layer thickness h of 0.3 λ -0.6 λ.
Fig. 7(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 45 deg. and a piezoelectric layer thickness h of 0.3 lambda-0.6 lambda.
Figures 8(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 50 deg. and a piezoelectric layer thickness h of 0.3 lambda-0.6 lambda.
Fig. 9(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 55 deg. and a piezoelectric layer thickness h of 0.3 lambda-0.6 lambda.
Fig. 10(a) - (d) show admittance diagrams of a lamb wave resonator for a piezoelectric layer cut angle of 60 deg. and a piezoelectric layer thickness h of 0.3 λ -0.6 λ.
Fig. 11 is a cross-sectional view showing the structure of a lamb wave resonator 200 according to another embodiment of the invention.
Detailed Description
The present invention will be described in detail below with reference to the attached drawings, and the features of the present invention will be further apparent from the following detailed description.
Fig. 1 is a schematic structural view of a surface acoustic wave interdigital transducer (IDT). As shown in fig. 1, a metal film is deposited on the surface of the piezoelectric substrate, and then a set of comb-shaped crossed metal electrodes is obtained by using a photolithography method in a semiconductor planar process. The metal electrodes in the shape of fingers are arranged in a mutually crossed mode, and bus bars are arranged at two ends of the metal electrodes to be connected together to form two stages of devices respectively, so that the interdigital transducer is obtained. In the example of fig. 1, the 6 metal electrodes numbered 1-6 are shown together, indicating that the interdigital electrode number of this interdigital transducer is 6, wherein the electrodes (also called fingers) numbered odd numbers (1, 3, 5) are connected together to form the positive input (or output) terminal (+ V in the figure) of the interdigital transducer, and the fingers of the electrodes numbered even numbers (2, 4, 6) are connected together to form the positive input (or output) terminal (V in the figure) of the interdigital transducer.
Several main parameters of saw interdigital transducers are: the number of finger pairs N (e.g., 3 for finger pair N in fig. 1), the width d of the metal finger, the half-cycle length L, and the gap width b of the adjacent finger (b-L-d).
Fig. 2 is a cross-sectional schematic view of a lamb wave resonator 100 according to one embodiment of the invention, taken transverse to the lamb wave resonator, along the line a-a, for example, as shown in fig. 1. As shown in FIG. 2, lamb wave resonator 100 may include a substrate 101, which substrate 101 may use a high acoustic velocity material, such as 4H-SiC or 6H-SiC, and constitutes a POI structure.
Above the substrate 101 is a pressAnd an electric layer 102 provided with first and second interdigital transducers (IDTs) on an upper surface and a lower surface of the piezoelectric layer 102, respectively, wherein interdigital electrodes (also simply referred to as upper electrodes and lower electrodes) of the first and second interdigital transducers are opposed to each other in a stacking direction via the piezoelectric layer 102, respectively, and have the same electrode width, electrode thickness, electrode pitch, and excited acoustic wave wavelength λ. In this example, the interdigitated electrodes are completely buried in the piezoelectric layer. As one example, the material of the piezoelectric layer 102 may be YX-LiNbO with a cut angle of θ3The tangent angle theta may be, for example, 30 deg. -60 deg.. The interdigital electrodes of the first and second interdigital transducers may be made of a metal or alloy of Ti, Al, Cu, Au, Pt, Ag, Pd, Ni, or the like, or a laminate of these metals or alloys. It will be understood by those skilled in the art that although only two electrode fingers are shown for both the upper and lower electrodes in fig. 2, this is merely for convenience of illustration, and in practice, the interdigital electrode of a lamb wave resonator typically has more than two electrode fingers (as shown in fig. 1) all having the same electrode width, electrode thickness, electrode spacing, and excited acoustic wave wavelength λ.
Fig. 3 is a partially enlarged schematic view of a lamb wave resonator. As shown in fig. 3, the upper and lower electrodes are all completely buried in the piezoelectric layer 102, and the thickness of the electrodes is 200 nm. The sum of the electrode width and the electrode spacing may be 0.5 λ, where λ is the excited acoustic wavelength of the electrode. The electrode width may be 0.25 λ. Further, for reference, in the present example, λ may be 2 μm, and the thickness of the substrate 101 is 5 λ. The thickness of the piezoelectric layer 102 can be 0.3 lambda-0.6 lambda.
In past attempts to improve the electromechanical coupling coefficient and the stray effect, the influence of the ratio of the electrode embedded in the piezoelectric layer on the electromechanical coupling coefficient and the stray effect has never been considered and explored, and even in the case of the electrode completely embedded in the piezoelectric layer, the influence of the combination of the thickness of the piezoelectric layer and the cut angle of the piezoelectric layer on the electromechanical coupling coefficient and the stray effect has not been considered and explored. FIGS. 4-10 show admittance plots for lamb wave resonators at different piezoelectric layer cut angles and different piezoelectric layer thicknesses, respectively, where the duty cycles are η, fsIs the resonant frequency, fp is the antiresonant frequency, center frequencyRate f0Can be calculated according to the following formula (1):
f0＝(fs+fp)/2 (1)
coefficient of electromechanical coupling k2It can be calculated by the following formula (2):
k2＝(π2/8)(fp2-fs 2)/fs 2 (2)
fig. 4(a) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 30 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in fig. 4(a), in the case where the piezoelectric layer has a chamfer of 30 ° and the piezoelectric layer has a thickness h of 0.3 λ, the resonance frequency fsAbout 2350MHz, an antiresonant frequency fpAt about 2716MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 41.38%.
Fig. 4(b) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 30 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in FIG. 4(b), in the case where the chamfer of the piezoelectric layer is 30 DEG and the thickness h of the piezoelectric layer is 0.4 lambda, the resonance frequency fsAt about 2188MHz, an antiresonant frequency fpAt about 2587MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2About 49.05%.
Fig. 4(c) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 30 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in FIG. 4(c), in the case where the chamfer of the piezoelectric layer is 30 DEG and the thickness h of the piezoelectric layer is 0.5 lambda, the resonance frequency fsAbout 2120MHz, antiresonant frequency fpAbout 2509MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 49.38%.
Fig. 4(d) shows an admittance diagram for a case where the cut angle of the piezoelectric layer is 30 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in FIG. 4(d), in the case where the chamfer of the piezoelectric layer is 30 DEG and the thickness h of the piezoelectric layer is 0.6 lambda, the resonance frequency fsAt about 2153MHz, antiresonant frequency fpAbout 2514MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 44.79%.
FIG. 5(a) shows the admittance for a chamfer of the piezoelectric layer of 35 DEG and a thickness h of the piezoelectric layer of 0.3 lambdaFigure (a). As shown in fig. 5(a), in the case where the cut angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.3 λ, the resonance frequency fsAbout 2354MHz, an antiresonant frequency fpAt about 2723MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 41.67%.
Fig. 5(b) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 5(b), in the case where the cut angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.4 λ, the resonance frequency fsAbout 2193MHz, antiresonant frequency fpAbout 2595MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 49.33%.
Fig. 5(c) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 5(c), in the case where the cut angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2123MHz, antiresonant frequency fpAbout 2516MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 49.85%.
Fig. 5(d) shows an admittance diagram for a piezoelectric layer chamfer of 35 ° and a piezoelectric layer thickness h of 0.6 λ. As shown in fig. 5(d), in the case where the chamfer angle of the piezoelectric layer is 35 ° and the thickness h of the piezoelectric layer is 0.6 λ, the resonance frequency fsAbout 2160MHz, the antiresonant frequency fpIs about 2521MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 44.64%.
Fig. 6(a) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in fig. 6(a), in the case where the chamfer angle of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.3 λ, the resonance frequency fsAbout 2360MHz, the antiresonant frequency fpAt about 2726MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 41.19%.
Fig. 6(b) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 6(b), in the case where the chamfer angle of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.4 λ, the resonance frequency fsIs about 2200MHzOf antiresonant frequency fpAbout 2599MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 48.76%.
Fig. 6(c) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 6(c), in the case where the chamfer angle of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2130MHz, the antiresonant frequency fpIs about 2520MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 49.26%.
Fig. 6(d) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in fig. 6(d), in the case where the chamfer angle of the piezoelectric layer is 40 ° and the thickness h of the piezoelectric layer is 0.6 λ, the resonance frequency fsAbout 2170MHz, antiresonant frequency fpIs about 2525MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 43.62%.
Fig. 7(a) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in fig. 7(a), in the case where the chamfer angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.3 λ, the resonance frequency fsAbout 2368MHz, the antiresonant frequency fpAt about 2725MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 39.96%.
Fig. 7(b) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 7(b), in the case where the chamfer angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.4 λ, the resonance frequency fsAt about 2207MHz, antiresonant frequency fpAbout 2599MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 47.67%.
Fig. 7(c) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 7(c), in the case where the chamfer angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2139MHz, the antiresonant frequency fpAbout 2519MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 47.68%.
Fig. 7(d) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in fig. 7(d), in the case where the chamfer angle of the piezoelectric layer is 45 ° and the thickness h of the piezoelectric layer is 0.6 λ, the resonance frequency fsAbout 2180MHz, the antiresonance frequency fpIs about 2526MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 42.23%.
Fig. 8(a) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in fig. 8(a), in the case where the chamfer angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.3 λ, the resonance frequency fsAbout 2377MHz, the antiresonant frequency fpAt about 2720MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2About 38.13%.
Fig. 8(b) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 8(b), in the case where the chamfer angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.4 λ, the resonance frequency fsAbout 2216MHz, anti-resonance frequency fpAbout 2595MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 45.76%.
Fig. 8(c) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 8(c), in the case where the chamfer angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2149MHz, an antiresonant frequency fpAbout 2515MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 45.56%.
Fig. 8(d) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in fig. 8(d), in the case where the chamfer angle of the piezoelectric layer is 50 ° and the thickness h of the piezoelectric layer is 0.6 λ, the resonance frequency fsAbout 2192MHz, antiresonant frequency fpIs about 2522MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2Is about 39.90%.
Fig. 9(a) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in FIG. 9(a)In the case where the cut angle of the piezoelectric layer is 55 DEG and the thickness h of the piezoelectric layer is 0.3 lambda, the resonance frequency fsAbout 2387MHz, the antiresonant frequency fpAt about 2711MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2About 35.73%.
Fig. 9(b) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 9(b), in the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.4 λ, the resonance frequency fsAbout 2225MHz, antiresonant frequency fpAt about 2587MHz, where the electromechanical coupling coefficient k can be calculated according to equation (2)2About 43.37%.
Fig. 9(c) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 9(c), in the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2162MHz, the antiresonance frequency fpAbout 2508MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 42.60%.
Fig. 9(d) shows an admittance diagram for the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in fig. 9(d), in the case where the cut angle of the piezoelectric layer is 55 ° and the thickness h of the piezoelectric layer is 0.6 λ, the resonance frequency fsAt about 2204MHz, antiresonant frequency fpAbout 2515MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 37.24%.
Fig. 10(a) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 60 ° and the thickness h of the piezoelectric layer is 0.3 λ. As shown in fig. 10(a), in the case where the piezoelectric layer has a chamfer of 60 ° and the piezoelectric layer has a thickness h of 0.3 λ, the resonance frequency fsAbout 2399MHz, the antiresonant frequency fpIs about 2700MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 32.87%.
Fig. 10(b) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 60 ° and the thickness h of the piezoelectric layer is 0.4 λ. As shown in fig. 10(b), in the case where the piezoelectric layer has a chamfer of 60 ° and the piezoelectric layer has a thickness h of 0.4 λ, the resonance frequency fsAbout 2233MHz, antiresonantFrequency fpAbout 2576MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 40.77%.
Fig. 10(c) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 60 ° and the thickness h of the piezoelectric layer is 0.5 λ. As shown in fig. 10(c), in the case where the chamfer of the piezoelectric layer is 60 ° and the thickness h of the piezoelectric layer is 0.5 λ, the resonance frequency fsAbout 2177MHz, antiresonant frequency fpAbout 2497MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 38.89%.
Fig. 10(d) shows an admittance diagram for the case where the chamfer of the piezoelectric layer is 60 ° and the thickness h of the piezoelectric layer is 0.6 λ. As shown in fig. 10(d), in the case where the piezoelectric layer has a chamfer of 60 ° and the piezoelectric layer has a thickness h of 0.6 λ, the resonance frequency fsAbout 2216MHz, anti-resonance frequency fpAbout 2503MHz, at which time the electromechanical coupling coefficient k can be calculated according to equation (2)2About 33.99%.
In Table 1 below, the resonance frequency f of the lamb wave resonator is counted for different piezoelectric layer cut angles and different piezoelectric layer thicknesses shown in the above figuressAnti-resonance frequency fp, acoustic velocity and electromechanical coupling coefficient k2Also given are the Q values in each case.
TABLE 1
It can be found that under different combinations of the cut angle theta of the piezoelectric layer and the thickness h of the piezoelectric layer, the following groups of values have obvious effects of improving the electromechanical coupling coefficient and the quality factor Q.
1. When the piezoelectric layer cut angle θ and the electrode piezoelectric layer thickness h are values in table 2, the electromechanical coupling coefficient of the lamb wave resonator is large, at least above 34%, and the main mode has no or little spurious.
| Piezoelectric layer corner cut θ (YX-LiNbO)3) | Thickness of piezoelectric layer (lambda) | Coefficient of electromechanical coupling k2(％) |
| 30°,50,60° | 0.6 | k2≥34％ |
| 35° | [0.3,0.4],0.6 | k2≥41.6％ |
| [40°,45°] | [0.3,0.6] | k2≥40％ |
| 55° | [0.5,0.6] | k2≥37.2％ |
TABLE 2
2. When the piezoelectric layer cut angle θ and the electrode piezoelectric layer thickness h are the values in table 3, the electromechanical coupling coefficient of the lamb wave resonator is large, at least above 37.2%, and the main mode has no or little spurs, which means that the spurs effect is suppressed, and the quality factor Q is high, at least above 535, as seen from the data.
TABLE 3
Fig. 11 is a cross-sectional view showing the structure of a lamb wave resonator 200 according to another embodiment of the invention. As shown in fig. 11, a lamb wave resonator 200 has a similar structure to the lamb wave resonator 100 except that a dielectric layer 103 is interposed between a high acoustic velocity substrate 101 and a piezoelectric layer 102. The dielectric layer 103 may be formed of a low acoustic impedance material having low acoustic speed, such as SiO2. The temperature coefficient of frequency of this dielectric layer 103 is positive and the temperature coefficient of frequency of the piezoelectric layer 102 is negative, so this dielectric layer 103 can lower the Temperature Coefficient of Frequency (TCF) of the lamb wave resonator. Further, the dielectric layer 103 has a low acoustic velocity and forms a reflective layer with the high acoustic velocity substrate 101, so that the acoustic wave can be prevented from leaking from the direction of the substrate 101, which contributes to obtaining a high Q value. As an example, the dielectric layer 103 may have a thickness of 0.075-0.1 λ.
Optionally, the lamb wave resonator may further be covered with a dielectric layer above the piezoelectric layer 102 by PECVD, CVD, or the like, where the dielectric layer may be SiO2SiN, etc. This dielectric layer may further reduce the Temperature Coefficient of Frequency (TCF) of the lamb wave resonator and may also act as a protective layer for the resonator.
What has been described above includes examples of aspects of the claimed subject matter. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the claimed subject matter, but one of ordinary skill in the art may recognize that many further combinations and permutations of the claimed subject matter are possible. Accordingly, the disclosed subject matter is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.
Claims (10)
1. A lamb wave resonator having a POI structure, the lamb wave resonator comprising:
a substrate of a high acoustic velocity material; and
a piezoelectric layer located above the high acoustic velocity material substrate, the piezoelectric layer having an upper surface and a lower surface on which a first interdigital transducer and a second interdigital transducer are respectively disposed, wherein interdigital electrodes of the first interdigital transducer and the second interdigital transducer are opposite to each other in a stacking direction across the piezoelectric layer and have the same electrode width, electrode thickness, electrode spacing, and excited acoustic wave wavelength λ, and the interdigital electrodes are all embedded in the piezoelectric layer, wherein
The piezoelectric layer is made of YX-LiNbO with a cut angle theta3Wherein θ is 30 ° ≦ θ ≦ 60 °, and the thickness t of the piezoelectric layer is 0.3 λ -0.6 λ.
2. The lamb wave resonator of claim 1, wherein said shear angle θ and the thickness t of said piezoelectric layer each take on one of the following combinations:
θ is 30 °, 50 ° or 60 °, t is 0.6 λ;
θ 35 °, t 0.3 λ -0.4 λ or 0.6 λ;
theta is more than or equal to 40 degrees and less than or equal to 45 degrees, and t is 0.3 lambda-0.6 lambda; and
θ＝55°，t＝0.5λ－0.6λ。
3. the lamb wave resonator of claim 1, wherein said shear angle θ and the thickness t of said piezoelectric layer each take on one of the following combinations:
θ＝35°，t＝0.3λ－0.4λ；
θ＝50°，t＝0.6λ；
θ is 55 °, t is 0.6 λ; and
θ＝60°，t＝0.6λ。
4. the lamb wave resonator of claim 1, wherein said high acoustic speed material is 4H-SiC, 3C-SiC or 6H-SiC.
5. The lamb wave resonator of claim 1, further comprising: a layer of low acoustic velocity material dielectric disposed between the high acoustic velocity material substrate and the piezoelectric layer.
6. The lamb wave resonator of claim 5, wherein said low acoustic velocity material is SiO2And the thickness is 0.075 lambda-0.1 lambda.
7. The lamb wave resonator of claim 5, wherein the piezoelectric layer is plated with a dielectric layer material on the other side surface of the piezoelectric layer opposite the substrate of high acoustic velocity material.
8. The lamb wave resonator of claim 7, wherein said dielectric layer material is SiO2Or SiN with a thickness of 0.05 lambda-0.1 lambda.
9. The lamb wave resonator of claim 1, wherein said wavelength λ is 2 μm.
10. The lamb wave resonator of claim 1, wherein said substrate of high acoustic velocity material has a thickness of 5 λ, said electrode width is 0.25 λ, said electrode spacing is 0.25 λ, and said electrode thickness is 200 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011508678.2A CN112702037A (en) | 2020-12-18 | 2020-12-18 | Lamb wave resonator with POI structure |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011508678.2A CN112702037A (en) | 2020-12-18 | 2020-12-18 | Lamb wave resonator with POI structure |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112702037A true CN112702037A (en) | 2021-04-23 |
Family
ID=75507522
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011508678.2A Pending CN112702037A (en) | 2020-12-18 | 2020-12-18 | Lamb wave resonator with POI structure |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112702037A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2012257019A (en) * | 2011-06-08 | 2012-12-27 | Murata Mfg Co Ltd | Elastic wave device |
| CN106209007A (en) * | 2010-12-24 | 2016-12-07 | 株式会社村田制作所 | Acoustic wave device and manufacture method thereof |
| CN112054781A (en) * | 2020-09-11 | 2020-12-08 | 广东广纳芯科技有限公司 | High-performance resonator with double-layer homodromous interdigital transducer structure |
| CN212163290U (en) * | 2020-04-01 | 2020-12-15 | 河源市众拓光电科技有限公司 | Scandium-doped aluminum nitride lamb wave resonator |
-
2020
- 2020-12-18 CN CN202011508678.2A patent/CN112702037A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106209007A (en) * | 2010-12-24 | 2016-12-07 | 株式会社村田制作所 | Acoustic wave device and manufacture method thereof |
| JP2012257019A (en) * | 2011-06-08 | 2012-12-27 | Murata Mfg Co Ltd | Elastic wave device |
| CN212163290U (en) * | 2020-04-01 | 2020-12-15 | 河源市众拓光电科技有限公司 | Scandium-doped aluminum nitride lamb wave resonator |
| CN112054781A (en) * | 2020-09-11 | 2020-12-08 | 广东广纳芯科技有限公司 | High-performance resonator with double-layer homodromous interdigital transducer structure |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11552615B2 (en) | Acoustic wave device | |
| US9035725B2 (en) | Acoustic wave device | |
| US9819329B2 (en) | Ladder-type surface acoustic wave filter including series and parallel resonators | |
| CN112702036A (en) | Lamb wave resonator with POI structure | |
| CN103891139B (en) | Surface acoustic wave apparatus | |
| KR101514742B1 (en) | Surface acoustic wave device | |
| JP3301399B2 (en) | Surface acoustic wave device | |
| US6946930B2 (en) | Surface acoustic wave device and electronic device using the same | |
| CN110120794B (en) | Elastic wave device, high-frequency front-end circuit, and communication device | |
| CN110880922B (en) | Two-dimensional ultrahigh frequency resonator | |
| JPWO2005086345A1 (en) | Boundary acoustic wave device | |
| JP2010011440A (en) | Acoustic wave device and high-frequency filter using the same | |
| WO2019198594A1 (en) | Acoustic wave element, acoustic wave filter, splitter, and communication device | |
| JP3391309B2 (en) | Surface wave device and communication device | |
| JPWO2011102128A1 (en) | Antenna duplexer | |
| CN113872562A (en) | Surface acoustic wave device | |
| CN112532205B (en) | Elastic surface wave resonator, filter and antenna sharing device | |
| JP5083469B2 (en) | Surface acoustic wave device | |
| CN110572138A (en) | Filtering device and manufacturing method thereof | |
| CN210405249U (en) | Filtering device | |
| JP5579429B2 (en) | Elastic wave device, communication module, communication device | |
| CN112600529A (en) | Lamb wave resonator with POI structure | |
| CN116232270A (en) | High-frequency multilayer film surface acoustic wave resonator | |
| CN112702037A (en) | Lamb wave resonator with POI structure | |
| CN115425942A (en) | Surface acoustic wave device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210707 Address after: 510700 Room 202, building D, No. 136, Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant after: Guangdong Guangna Technology Development Co.,Ltd. Address before: 510700 room 1004, building D, 136 Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant before: Guangdong guangnaixin Technology Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210811 Address after: 510535 Room 201, building D, 136 Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant after: Guangdong Guangdong Guangdong Hong Kong Macao Dawan District National Nanotechnology Innovation Research Institute Address before: 510700 Room 202, building D, No. 136, Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant before: Guangdong Guangna Technology Development Co.,Ltd. |
|
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20210913 Address after: 510700 room 1004, building D, 136 Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant after: Guangdong guangnaixin Technology Co.,Ltd. Address before: 510535 Room 201, building D, 136 Kaiyuan Avenue, Huangpu District, Guangzhou City, Guangdong Province Applicant before: Guangdong Guangdong Guangdong Hong Kong Macao Dawan District National Nanotechnology Innovation Research Institute |